1. Field of the Invention
One embodiment of the present invention relates to a semiconductor device or a memory device.
Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. In addition, one embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter. One embodiment of the present invention relates to a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, a circuit board, an electronic device, a driving method thereof, or a manufacturing method thereof.
2. Description of the Related Art
A dynamic random access memory (DRAM) stores data by supply of electric charge to a capacitor. Thus, the off-state current of a transistor for controlling the supply of electric charge to the capacitor is preferably small. This is because the smaller the off-state current of the transistor is, the longer the data holding period can be; thus, the frequency of refresh operations can be reduced. Patent Document 1 discloses a semiconductor device that can hold stored content for a long time by using a transistor including an oxide semiconductor film and having extremely small off-state current.